Immunoproteomics And Temperature Comparative Proteomics Of Shigella Flexneri

Shigella is a genus of gram-negative bacilli that causes bacillary dysentery in humans by invading and replicating in epithelial cells lining the lower gut. Shigella infection spreads by the fecal-oral route. Because of the low infectious dose (10 to 100 organisms), person-to-person transmission probably is the most common. Worldwide there are approximately 164.7 million cases, of which 163.2 million in developing countries. Each year 1.1 million people are estimated to die from Shigella infection. In developing countries, S. flexneri 2a is most common. Because of the unknown mechanism of pathogenicity and immunoprotection, no ideal and effective vaccine has been developed till now.In this article immunoproteomic techniques were used to screen antigens of S. flexneri 2a 2457T. Whole cell proteins, membrane proteins, outer membrane proteins and extracellular proteins were extracted and performed 2-DE of different pH gradient. Reference map of OMPs were established and analyzed by software. Total 126 spots were calculated on 18cm pH 4-7 gel, 109 spots were cut and in-gel digested. Eighty-seven spots were identified successfully by MALDI-TOF/MS which represent 55 protein entries. The comparison between experimental and theoretical pI/MW distribution and their cellular role were analyzed. By using the sera of immunized rabbits, Western Blotting were performed with proteins of different components. Total of 23 antigens were found, 8 were known and 15 were unknown. One hypothetical protein-YaeT, with unknown function and strong immunoreactivity, was homologous with surface antigen D15 of Haemophilus influenzae and Oma87 of Pasteurella multocida. The transcription of yaeT was reported highly increased in a murine model and this gene was deduced associated with Shigella invasion.The expression of virulence genes of Shigella is temperature-dependent. Availability of invasion into Henle cells was reported when cultivated at 37℃ but not at 30℃. By using our improved methods, the whole cell proteins of bacteria cultivated at 30 and 37℃ were performed 2-DE. Fifty-nine different spots were found, which representing 53 protein entries by comparison of the 2-D gels. Forty-two proteins were up-regulated when cultivated at 30℃ and 12 were down-regulated at 37℃ (TufB was observed both of up-regulated and down-regulated). From the results we can deduce that the glyoxylate cycle pathway was...